Railway signaling track-circuit regulator



Sept. 23, 1930. s, LUCAS 1,776,684

' RAILWAY SIGNALING TRACK CIRCUIT REGULATOR Original Filed Nov. 22, 1927 1 a Ta talum-\ Lead I INVENTOR 2 5.11Lucas Chi-W Patented Sept. 23, 1930 V UNITED STATES.

SAMUEL vr. LUCAS, or rrr'rssunen, 1 ENl sYIivAlTIlt, ilSSIGrNOR' 'IQi THE nion; SWITCH & SIGNAL COMPANY, or SWISSVALE, rnmvsrnvamag a conroaa'rrou or PENNSYLVANIA.

RAILWAY SIGNALING TRACK-CIRCUIT em -mas Original application filed November 22, 1927, Serial no-. 2s4,9 5. D ide "and this -applicationinlelj December 12, 1929.

My invention relates to railway signaling track circuit regulators, and has for an object the provision of novel and improved means for preventing excessive energization of the track relay when the track ballast is dry, and, consequently, has relatively high resistance.

The present application is a division of my copending application filed November 22, 1927, for railway signaling track circuit regulators Serial No. 234,985.

I will describe one form of track circuit regulator embodying my invention, and will then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view showing a track circuit having applied thereto one form of regulator embodying my invention.

Referring to the drawing, the reference characters 1 and 1 designate the track rails of a railway track, which rails are divided by insulated joints 2 to form a track section.

This section is provided with a track circuit comprising the rails of the section, a source of current connected across the rails at one point, and a track relay R having a it is necessary to so adjust'the source of current that it will maintain the normal operating voltage across the relay winding during the lowest value of ballast resistance, that is, during the time of maximum saturation of the ballast with water. WVhen the ballast resistance rises, however, the voltage across relay R will also rise, and this may result in over-energization of the relay with consequent injurious efl'ects unless means are provided to prevent an increase of current in the relay due to increase of voltage across the SeriaLNo. 41339441 pg connected with; the rails.

V In aeeo ga ne w' 11 my invention, p? vide regulator connected across the rails adjacent therelay'and so adjustedS'as'tO con duct current when and onlywhen th'evoltage across the relay winding rises a given amount above thenormal operating value. As shownin the drawing, this [regulator comprises two electrolytic cells C and C each havingfa tantalum electrode and a lead electrode, im? mersed in a solution of sulphuric acid 6. f A cell of this character has a much higher resistance'in one direction thanninf'the other direction, and,conseqi1ently, it is necessary to oppositely connect two cells" in multiple. when the source of currentfor the track; circuit is alternating. These cells areof s lch nature that a gas 'is evolved when .currentiflows' as over-voltage. When the applied potential exceeds the over-voltage, the current which flows through the cell is limited only by the internal resistance of the cell, that is,

' E-e i i I" I r potential, e is theover-voltage, and r; is the internal resistance of the ;;cell.' Considering this equation, it is obvious that when E is a variable between zero and maximum, no current will flow through the cell until E exceeds 6, but when E does exceed 6, if r is small, the current through the cell will increase very rapidly with increase of E. The combination of electrodes and electrolyte is so chosen that e, the over-voltage of the cell, is slightly higher than the normal operating voltage of the relay R. It follows that when the ballast resistance is low, no current will flow through the cells C and G and the relay R will then receive all of the energy transmitted to the relayend of the track section. When the ballast resistance rises, however, current will flow through the cells as soon as the potential across the relay exceeds the overvoltage of the cells.

tioning the cells to the teristics, the cells can be made to prevent any i in which equationE is the applied,

By suitably proportrack circuit characdecided increase in the current through the relay, and so to prevent injurious effects on the relay due to over-energization. I

Although I have herein shown and described only one form of track circuit regulator embodying my invention, it is understood that various changes and modifications may 7 be madetherein within the scope of the ap- I pended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what- I claim is: o

1. In a railway signaling track" circuitof the type comprising track rails, a track relay having a winding connected across said rails, and a source of current also connected across said rails and adjusted to maintain the normal operating voltage across said relay winding during the lowest value of ballast re- 26 sistance, the combination with the aforementioned instrumentalities of an electrolytic cell connected across said rails and comprising a lead electrode and a tantalum electrode in a sulphuric acid solution, said cell being 25 adjusted to conduct current when and only whenthe voltage across said relay winding rises a given amount above the normal operating value. I

2. In a railway signaling track circuit of so the type comprising track rails, a track relay having a winding connected across said rails, and a source of alternating-current also connected across said rails and adjusted to maintain'the' normal operating voltage across said relay windingduring the lowest value of ballast resistance, the combination'with the aforementioned instrumentalitiesof two electrolytic rectifiers oppositely connected in multiple acrosssaid rails and each adjusted to conduct current when and only when they voltage across said relay winding rises a given amount above the normal operating value.

In testimony whereof I afiix my signature. SAMUEL M; LUCAS. 

